Thomas a



UNITED THOMAS EDISON, OF LLEWELLYNPARK, NE JERSEY.

METHODOF MAGNETiCALLY sEPARATme ones;

- ermine-Arlen forming part of L tters Patent no.

1892. Serial Ho. aortas; (su emen n Application illed July 20,

To all whom it 'may concern: Be it known that I, THQMAsA. EDISON, a

I citizen of the United Statesfl'es'iding at Llew- .of New Jersey, have ellyn Park, in the county of Essex and State invented s. certain new and useful Improvement in Treating Iron Ores, (Case No. 957,) of which the following is a specification.

The object of this invention is to eliminate, practically, the sulphur from concentrated iron ores where the original crude ore contains magnetic pyrites.

the results obtained the interior of the lumps Heretofore the crude ore in the form of large pieces and containinginn-go quantity of gangne has been roasted to acccmplishthe elimination of the sulphur; hut. this roasting,

process is an expensive one, and in additionare fer from perfect, since the pyrites on are protectedjfrom the oxidizing influence oi" the air.

In carrying out my invention the crude ore is first crushedto a suflicient degree of fineness tnf-remthe magnetic iron ore from the gangue and from the magnetic pyrites. The crushed ore is'then passed through a magnetic separator which is suficiently powerful to attract an the magnetic pyrites as well as the magnetic oxide of iron, thus eliminating the major portion of the non-magnetic gengue and leaving a concentrate composed of magnetic iron ore and magnetic pyrites with very little gangne. This concentrate isthen passed through a second magnetic separator, which is graduated to such a magnetic strength that, only the free particles of magnetic iron ore;

will be drawn away; leaving the i'nagnetio pyrites and such particles 0! iron ore as have pieces of non magnetic gangue- -snch as quartzclinging, to..them,. I have'found that there is a sulfici'ent difference in the specific magnetic capacity ofi the oxide of iron an the pyritesto allow of this differentiation. The iron ore obtained in this way as the product oil?l this fronieulp If the amount of iron in the .tailings'whichresultfrom the. second separathe crushed material to such strength that, due to the dill-Terence in cl-9s will be acted V pyrites particles will not be wise npon,

differential separation is tree 485,841, dated November 8, 1892.

tion is considerable, these tsiiings may then he roasted, so as to render the pyrites nonmagnetic, snd the magnetic be separated from the non-magnetic pyrites iron ore can then 5o by passing the material through a. magnetic separatogthns may he recrushed 0nd magnetic separation free eachironjore to a smaller size, so as to particle, when thedifference in themag netisni.

of the pyrites and magnetic oxide can again be taken eidventege of to separate the ironore particles from the pyrites particles by running the material through a magnetic separator oi the proper strength to accomplish thedifierenti'si separation, thus eliminating the whole of the-magnetic pyrites without the necessity of roasting,

'iwhat lelaimns my invention is 1. Thorn-cease of separating magnetic oxide of iron from megnetic pyrites where both occur inthe-same-.cre-,Vconsisting in subjecting specific magnetic capacityofi' the oxide of magnetic action 0! eliminating the whole of the pyritcs, or the residue or railings of the sec iron and the pyrites, the cxide-ef-iron pentithe magneticupon, whiie substsntialiy nssei'iorth. I

' The processof treating ores containing then passco'ne'isting in first crushing the cre,

Y in]; it, through a rnagnetic separator of snfli cien tst 'ren th'to separate the entire magnetic of the oxide'of. iron and the pyrites, the oxideof-iron particles will be separated from the pyrites particles, substsntislly as set forth.

d This specification signed andwitnessed this magnetic oxide of ironand magnet c pyrites, i

rnst'erisl from the nonmagnetic gangue, and then psssingithc concentrated ore through a magnetic separator of such strength that, due to the difference in specific magnetic capacity 

